Project Summary: Irreversible electroporation (IRE) is a novel tumor ablation method that uses ultrashort and strong electric fields to induce permanent damage to cell membranes and subsequent cell death. It offers several unique advantages including fewer side effects, less morbidity, and a faster recovery, but its clinical applications are severely limited by the bulky and complex electrical system. Innovations that are more effective, more ubiquitous, and in vivo applicable are urgently needed to revolutionize the IRE treatment, and eventually make this promising strategy a practical tumor treatment regimen. In this project, we proposed to demonstrate the feasibility and to investigate the efficacy of an ultrasound-activated cell-level IRE tumor treatment technology using a well-engineered piezoelectric P(VDF-TrFE) (polyvinylidene fluoride-trifluoroethylene copolymer) nanoparticle (NP) system. The proposed research is built on a hypothesis that the strong and highly localized electric field generated by piezoelectric NPs can achieve IRE on adjacent cell membranes, and thereby leads to cancer cell ablation. We envision that under the agitation of ultrasound waves, soft piezoelectric NPs will be strained and generate a strong electric field around them. These NPs individually act as a very localized pulsed electric field (PEF) generator. When the NPs move closer or attach to a cancer cell, the strong PEF will enable the IRE process locally and induce cell death. In Specific Aim 1, We will synthesize piezoelectric P(VDF-TrFE) NPs with controlled size from a few hundred nanometers to ~50 nm, tunable mechanical modulus, and optimized water dispersibility. The cancer cells targeting capability and the NP size related cytotoxicity on normal cells in the tumor microenvironment will be investigated. In Specific Aim 2, we will obtain quantitative understanding of NP?s mechanical modulus in correlation to the internal porosity, and the NP?s piezoelectric properties in correlation to the NP?s size, porosity and mechanical property. Eventually we will quantify the electric field generated by NPs in phosphate-buffered saline (PBS) solution under ultrasound waves as a function of ultrasound frequency and intensity. In Specific Aim 3, we will test the main hypothesis of this proposal by in vitro investigating the feasibility, and quantifying the effectiveness, selectivity, and impact range of cancer cell killing using ultrasound-driven NP-IRE on a series of selected cancer and normal cells. This proposed project will deliver a new type of biocompatible piezoelectric soft nanomaterial with a new prospective for treating cancers. Success of this project can open many new research and application opportunities for in vivo IRE tumor treatment and beyond, where electromechanical coupling is essential.